Improvement of a Set of 13Cr11Ni2W2MoV Steel Mechanical Properties for Critical Components of Stop Valves of Oil and Gas Pipelines Using Intercritical Quenching

A heat treatment regime for steel 13Cr11Ni2WMoV quenched from 980°C with the aim of simultaneous achievement of the required values of impact toughness and strength is investigated. It is established that the optimum condition of the heat treatment regime after high-temperature quenching is double tempering, the first of which is above A_c1 and is intercritical tempering. It is demonstrated that an increase in the first tempering temperature improves impact strength considerably in the final condition, and a reduction in second tempering temperature improves steel strength. A new heat treatment regime is proposed with which the temperatures of two-stage tempering are 765 and 635°C. Mechanical property values are achieved satisfying component specifications and there is a reserve for impact strength that is important for large components.